.header-nav{
    width: 100%;
    position: absolute;
    transition: transform .3s ease-in;
    .social {
        margin-right:15px;
        margin-top:10px;
        text-align: center;
        a {
            border-radius:50%;
            display:-moz-inline-stack;
            display:inline-block;
            vertical-align:middle;
            *vertical-align:auto;
            zoom:1;
            *display:inline;
            text-indent:-9999px;
            margin:0 8px 15px 8px;
            opacity:0.7;
            width:28px;
            height:28px;
            transition:0.3s;
            &:hover {
                opacity:1
            }
        }
        a:last-of-type {
            margin-right:0
        }
        a.weibo {
            background:url('./img/weibo.png') center no-repeat #aaaaff;
            border:1px solid #aaaaff;
            &:hover {
                border:1px solid #aaaaff;
            }
        }
        a.rss {
            background:url('./img/rss.png') center no-repeat #ef7522;
            border:1px solid #ef7522;
            &:hover {
                border:1px solid #cf5d0f;
            }
        }
        a.github {
            background:url('./img/github.png') center no-repeat #afb6ca;
            border:1px solid #afb6ca;
            &:hover {
                border:1px solid #909ab6;
            }
        }
        a.facebook {
            background:url('./img/facebook.png') center no-repeat #3b5998;
            border:1px solid #3b5998;
            &:hover {
                border:1px solid #2d4373;
            }
        }
        a.google {
            background:url('./img/google.png') center no-repeat #c83d20;
            border:1px solid #c83d20;
            &:hover {
                border:1px solid #9c3019;
            }
        }
        a.twitter {
            background:url('./img/twitter.png') center no-repeat #55cff8;
            border:1px solid #55cff8;
            &:hover {
                border:1px solid #24c1f6;
            }
        }
        a.linkedin {
            background:url('./img/linkedin.png') center no-repeat #005a87;
            border:1px solid #005a87;
            &:hover {
                border:1px solid #006b98;
            }
        }
        a.zhihu {
            background:url('./img/zhihu.png') center no-repeat #0078d8;
            border:1px solid #0078d8;
            &:hover {
                border:1px solid #0078d8;
            }
        }
        a.douban {
            background:url('./img/douban.png') center no-repeat #06c611;
            border:1px solid #06c611;
            &:hover {
                border:1px solid #06c611;
            }
        }
        a.mail {
            background:url('./img/mail.png') center no-repeat #005a87;
            border:1px solid #005a87;
            &:hover {
                border:1px solid #006b98;
            }
        }
    }
}